If you’re like a lot people, you might suffer from gephyrophobia, or a fear of bridges. Whether it’s heights or a fear of collapsing, crossing one can be nerve racking. Many are simply afraid of the unknown—the possibility that something might go wrong. These fears aren’t totally unfounded either, according to a 2015 analysis, 61,000 American bridges are deemed “structurally insufficient.” While this could mean a number of things, it’s much higher than we’d like to see. However, new techniques from a familiar source might help put gephyrophobes at ease and help bring this number down. Magnets can now help detect warning signs of potential collapses and prevent them! The Problem One reason bridges collapse has nothing to do with how they’re constructed or even how much traffic they see. In many cases, it’s something called foundation scouring. When you hear about bridges being swept away, it is usually because of scour. Foundation scouring occurs when all of the silt, sand, and dirt on the riverbed moves away from the support columns of the bridge, creating a crater of sorts and leaving the bridge’s base more vulnerable to erosion, rust, and even a river’s current. When these foundations are weakened, bridges are much more likely to collapse. The good news is that foundation scouring is pretty easy to fix. Simply dumping rocks or other materials (known as riprap) around the column’s base eliminates the problem. The only problem is that determining whether or not foundation scouring occurs used to require a team of divers to eyeball it. This can prove both hard to do (rivers and lakes can be very murky) and dangerous (risks of strong currents and even drowning).    The Solution Many scientists and engineers have weighed in on the problem of foundation scouring. One option is to bury long metal rods into the riverbed. These rods would then sway with the current. As erosion occurs around the bridge, more of the rods are exposed and the sway becomes greater. Engineers could monitor these sways and tell how much sediment has been washed away. But another solution proposed by Professor Genda Chen of Missouri S&T, piques our interest. Namely because it employs the help of magnets! Engineers would throw artificial “rocks” into the river, allowing them to come to rest where they will. Typically, the rocks would fall into craters and other areas of erosion. Sensors on the bridge would be used to detect the rocks’ magnetic fields, telling engineers where erosion around the bridge is at its worst and allowing preventive measures to be taken. While this idea is more costly than metal rods, it offers a more realistic picture of the river bottom and can help engineers to proactively, and more accurately, address issues of bridge scouring.   Infrastructure is one of the foundations of American life. Many of us, despite our fears, rely on bridges in our daily lives. In a seemingly never-ending quest to improve them and make them safer, it’s great to see magnets playing a role! For more magnetic news and facts, make sure to check out the rest of our News and How-To’s section! Image by Shuvaev